In pharmaceuticals and similar fields, preparative separation-purification systems employing liquid chromatographs are used in order to collect samples of various lands of chemically synthesized compounds which are to be stored in a library or subjected to detailed analyses. For example, the systems disclosed in Patent Documents 1 and 2 have been conventionally known as this type of preparative separation-purification system.
In a preparative separation-purification system, target components (compounds) in a sample solution are temporally separated by a liquid chromatograph. The separated target components are individually introduced into separate trap columns and temporarily captured in those columns. Subsequently, a solvent (“eluting solvent”) is passed through each tap column to quickly elute the component captured in the trap column. Consequently, a plurality of solutions, each of which contains one target component at a high level of concentration, are collected in separate containers (“collection containers”). These separately collected solutions are subjected to a vaporizing and drying process to remove the solvent and collect the target components in solid forms.
Before and after the aforementioned process of eluting the target component from the trap column (which is hereinafter called the “eluting treatment”), the “pretreatment” and “posttreatment” phases are respectively performed. In the pretreatment phase, a predetermined kind of pretreatment liquid (which is selected according to the kind of target component) is passed through the trap column before the eluting treatment in order to wash away components other than the target component present in the trap column (“contaminants”). In the posttreatment phase, the trap column which has undergone the eluting treatment is rinsed with a predetermined kind of posttreatment liquid in order to make it ready for reuse.
In such a preparative separation-purification system, a needle having an internal passage for a liquid is used to pass the pretreatment liquid, eluting solvent and posttreatment liquid through the trap column. The needle has a tip portion which is tapered toward the tip and a base end to which a flexible tube made of a resin or similar material is connected. On the other hand, the trap column has a needle port made of a resin or similar material at its inlet end. By holding the trap column in an upright position with the inlet end directed downward and inserting the tip of the needle into the needle port of the column from below, the tube can be connected to the tap column. The needle port has a vertically penetrating passage formed inside. At the lower (inlet) end of tins passage, a funnel-like portion whose diameter decreases upward is formed. As noted earlier, the tip portion of the needle is tapered. Therefore, when the needle which has been inserted into the passage of the needle port from below reaches a certain height during its upward motion, the outer circumferential surface of the tip portion of the needle comes in close contact with the inner circumferential surface of the funnel-like portion of the passage, whereby a liquid-tight connection is seemed.